With the implementation of the new energy strategy, electric vehicles are being widely used. Lithium-ion batteries are well applied for their excellent power output characteristics and long service life. However, the performance of high-capacity, high-power lithium-ion batteries are sensitive to temperature changes. The space is limited, the number of batteries is large and they are closely arranged and connected. When the vehicle is running under different driving conditions, the batteries will discharge at different rates, generate a qlarge amount of heat at different heat generation rates, considering accumulation of time and influence of limited space, uneven heat accumulation will occur, resulting in complex and variable battery operating environment temperature. If this situation lasts for a long time, overcharge and overdischarge of some batteries would occur, which will affect the life and performance of the batteries and cause safety hazards.
With the miniaturization and micro-miniaturization of electronic components as well as the high integration and micro-assembly of integrated circuits, the heat flux density of devices and components is constantly increasing, and thermal design thereof is facing severe challenges. Heat dissipation problems are present in the technical field such as radiation transmitters, high-power electronic devices, chips, data room equipment, high-power power supplies, IGBTs, transformers and the like.
High-power devices such as electronic power modules, battery power supplies, and electronic chips generate heat during operation that must be carried away by the cooling device to prevent the temperatures from exceeding their safe working limits. The current high-power heat dissipation structure has the following technical defects:
1. Since the electronic device needs insulation protection, the cooling coolant used in the current cooling device is in indirect contact with the heat sink member. Heat-conductive silicone grease, heat-conductive oil, the metallic heat sinks (for receiving heat), etc. are necessary as the intermedium for heat transfer, and mostly forced air cooling is used for the heat dissipation. The conventional heat-dissipating cooling device increases the thermal resistance due to the presence of the intermedium. If the heat cannot be dissipated in time, it is easy to cause high-power heat accumulation, which causes the junction temperature of the electronic device to rise and thus causes damage.
2. When air forced convection cooling is used, the heat conductivity of air is much lower than that of liquid, and it is necessary to install a power consumption device such as a fan to achieve forced convection of ambient air. The technology indirectly cools the heat generation body by cooling the environment space where the electronic device is located, and the heat exchange conditions and the heat exchange efficiency are limited. Also, the forced convection device such as the fan consumes a part of the electric power, and the power consumption increases as the heat dissipation power increases.
3. Due to the forced convection circulation of air, the environment in which the electronic device is located requires for high air cleanliness.